Process for continuous bleaching of fibrous materials



Nov. 15, 1932. E. EKEBERG 1,887,587

PROCESS FOR CONTINUOUS BLEACHING OF FIBROUS MATERIALS Filed Aug. 27, 1950 40 at the periphery of Patented Nov. 15, 1932 UNITED STATES mun ,EKEBIBG, or xonea, swarm;

PROCESS FOR CONTINUOUS BLEACHING OI FIBBOUS,

Application filed August 27, 1930, Serial 110.. 478,250, and in Sweden September 6, 198a,;

treatment, the bleaching or removal of nondesirous ingredients in the fibrous mass being performed without any mechanical action on the same, and the fibres and bleaching fluid being left entirely at rest in relation to each other, so that hydration and similardamages to the material is substantially avoided and the loss of fibres reduced to a minimum.

In the following the invention is to be explained in connection with an apparatus suitable for carrying the same into efiect, such apparatus being shown in the accompanying diagrammatical drawing, wherein Fig. 1 shows the apparatus in vertical section, and

Fig. 2 shows a plan view of the same.

The apparatus consists of an annular container or trough a open in upward direction and mounted at the periphery of a horizontal turntable b which is rotatable around a 3 central shaft 0'. Adjacent to its circumference such turntable at its under side is provided with a number of wheels or rolls d running on a circular rail 6 and adapted to support the turntable during its rotation. The driving power for causing the rotational movement of the turntable is suitably transmitted from a gear transmission f, g, h coacting with a circular'toothed rack positioned the turntable a.Naturally, the driving means may also be constructed in several other ways, if found convenient.

For the chargin and discharging of the 5 material to be bleac ed, which material hereinafter may be termed the pulp for the sake of convenience, suitable conveyor means i and y are provided substantially as indicated in the embodiment of invention shown in the drawing. According to this embodiment the said conveyor means are supposed to con-' -ly advancing said support together with the sistof a stationary tube 1' having its-open positloned above the annular trough 'a and; enclosing a screw conveyor, such means he ing adapted for the charging of the trough a and serves for the continuous discharge;

of the pulp. 4

The bleaching process is performed as follows The concentrated pulp mixed' with bleach-. ing fluid is continuously introduced into the rotating trough a and is carried round by the same until it reaches the elevator by which it is discharged from the apparatus and sub jected to suitable subsequent treatment,' for instance a second bleaching in common, beaters. The temperature is controlled by the addition of hot water, and the speed of rotation of the trough is adjusted according to the period of time required for the bleaching, as the pulp is carried round one revolution I during the process.

By means of the invention an entirely continuous working and a constant minimum time of bleaching, are obtained even if mishaps vshould occur in the machines preceding the bleaching apparatus in the treatment of the pulp. During the bleaching, the pulp is not subjected to any mechanical action, and hereby a low degree of hydration and loss of fibrous material are obtained. Besides the apparatus described involves a substantial reduction of the power consumption required, and it is cheap in manufacture and maintenance. 1

The rotating annular-channel formed the trough may naturally also be substituted by an endless belt, wire'netting or the 9 1 The method of bleaching paper pulp and the like which comprises mixlng a, continuous stream of pulp with a continuous stream of bleaching liquor, continuously discharging the mixture on to a support, continuousmixture and with the fibers and bleaching liquor therein entirely at rest relatively to each other, and continuously discharging the bleached pulp from said support.

2. The method of bleaching paper pulp and the like, which comprises mixing a continuous stream of pulp with a continuous stream of bleaching liquor, continuously discharging the mixture on to a support, continuously advancing said support at a constant speed together with the mixture and with the fibers and bleaching liquor therein entirely at rest relatively to each other, and continuously discharging the bleached pulp from said sup port after a definite period of time.

In testimony whereof I have signed my name to this specification.

EMIL EKEBERG. 

